internal static GifExtension ReadExtension(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
int extensionLabel = stream.ReadByte();
if (extensionLabel < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
int num2 = extensionLabel;
if (num2 == 1)
{
return(GifPlainTextExtension.ReadPlainText(stream, controlExtensions, metadataOnly));
}
if (num2 == 0xf9)
{
return(GifGraphicControlExtension.ReadGraphicsControl(stream));
}
switch (num2)
{
case 0xfe:
return(GifCommentExtension.ReadComment(stream));
case 0xff:
return(GifApplicationExtension.ReadApplication(stream));
}
throw GifHelpers.UnknownExtensionTypeException(extensionLabel);
}
internal static GifExtension ReadExtension(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
// Note: at this point, the Extension Introducer (0x21) has already been read
int label = stream.ReadByte();
if (label < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (label)
{
case GifGraphicControlExtension.ExtensionLabel:
return(GifGraphicControlExtension.ReadGraphicsControl(stream));
case GifCommentExtension.ExtensionLabel:
return(GifCommentExtension.ReadComment(stream));
case GifPlainTextExtension.ExtensionLabel:
return(GifPlainTextExtension.ReadPlainText(stream, controlExtensions, metadataOnly));
case GifApplicationExtension.ExtensionLabel:
return(GifApplicationExtension.ReadApplication(stream));
default:
throw GifHelpers.UnknownExtensionTypeException(label);
}
}
internal static GifBlock ReadBlock(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
int blockId = stream.ReadByte();
if (blockId < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (blockId)
{
case GifExtension.ExtensionIntroducer:
return(GifExtension.ReadExtension(stream, controlExtensions, metadataOnly));
case GifFrame.ImageSeparator:
return(GifFrame.ReadFrame(stream, controlExtensions, metadataOnly));
case GifTrailer.TrailerByte:
return(GifTrailer.ReadTrailer());
default:
throw GifHelpers.UnknownBlockTypeException(blockId);
}
}
internal static GifBlock ReadBlock(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
int blockId = stream.ReadByte();
if (blockId < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
int num2 = blockId;
if (num2 == 0x21)
{
return(GifExtension.ReadExtension(stream, controlExtensions, metadataOnly));
}
if (num2 == 0x2c)
{
return(GifFrame.ReadFrame(stream, controlExtensions, metadataOnly));
}
if (num2 != 0x3b)
{
throw GifHelpers.UnknownBlockTypeException(blockId);
}
return(GifTrailer.ReadTrailer());
}